Gas or renewables – we need both for now

Newspaper articles have recently hit out at an apparent willingness of the government to allow more gas-fuelled power plants.  Critics fear this indicates a weakening of support for renewables.  I’m less certain.

The UK is way behind many other countries in weaning ourselves off fossil fuels.  The North Sea bonanza – encouraged by Margaret Thatcher’s tax-cutting regime – meant that while other countries’ reaction to the oil price spike in the 1970s was to look to renewables, the UK bathed in cheap gas and oil and didn’t look to the future.

This plant takes in food waste from local councils, shops, manufacturers and caterers and produces gas anaerobically which it puts through gas turbines to make ‘green’ electricity which it sells.

But now the picture is changing.  Our oil and gas are waning fast – we’ve been net importers for most of this century.  Oil prices peaked again in 2008, sending a shock through the world economy.  The financial and energy cost of future oil and gas supplies – from increasingly remote and difficult areas – mean that lower prices are not expected to return as I have explained before.

To insulate us and our economy from future shocks means we need to stop being dependent on fossil fuels.  People are talking about renewable electricity as the alternative – from wind, solar, wave, tidal and hydro.

There are two problems. 

  • One is that we have nothing like enough ‘installed capacity’.  We need to build many more windfarms and more solar roofs, more tidal barrages and put more turbines on river weirs.  All this takes time, as we balance need against impact through our planning system and available finance.
  • the second is intermittency; the wind doesn’t always blow, waves come and go, tides wax and wane and the sun only shines during the day, and even then may be obscured by clouds.

Critics of renewables cite these as reasons why they can never replace fossil fuels or nuclear power.  But they must, if we are to maintain an available electricity supply.  Both fossil fuels and uranium are finite resources, and we need to preserve them to avoid runaway climate change and be able to fuel global trade (see my previous article “Investment in nuclear technology for shipping“.)

So what’s the solution?

Continuing to install more renewable generating capacity – and indeed to develop this technology – remains a priority.  This is part of the ‘green economy’ which is showing stronger growth than the general economy, but more investment is clearly still needed.  It is important that the government gives business the confidence to lead on this investment…

However, even the optimistic think it is unlikely that this investment will meet the necessary timescales.  Ofgem has recently warned that too slow an investment in new generating capacity risks shortages of electricity by around 2015.  And we’ve still not solved the intermittency problem.

Again there are multiple options here.  Load-shedding can be a significant element.  Boosting the grid by using stored electricity in electric car batteries and even laptops.  Extending the international grid, to use power from much further afield, where the wind may still be blowing.  And some hydroelectric plants can also help fill these gaps, but not usually for long. 

The trouble is that electricity is very expensive to store, and just storing it means losing some of the energy.  But we can store gas.

And we can make gas; gas can also be a ‘renewable fuel’. 

Natural gas is mostly methane, with a little hydrogen and smaller amount of other gases.  If we have too much renewable electricity – for example if there is lots of wind and sunshine and less demand for electricity – then we could make hydrogen and store it for later, and there are also systems being developed to turn this hydrogen into methane and longer chain hydrocarbons.

There are also already biogas plants feeding into the gas grid: making gas from plant and animal material being broken down anaerobically (without oxygen).  This can be from farm waste or sewage, and from food waste.  Gas can also be made by ‘cracking’ long chain hydrocarbons in plant material or even domestic waste, in a similar way that heavy fuel oils can be ‘cracked’ in oil refineries to make lighter factions like petrol and aviation fuel.

To make use of this stored renewable energy we then need gas-fired power plants.

Indeed, gas-fired electricity generation – using gas turbines – has another advantage:  Gas turbines can be powered up and powered down (that is, switched on and off) much more quickly than coal or nuclear plants.  This means that as the sun sets, or wind drops, gas  plants can be quickly powered up to keep the electricity supply and demand in balance.   

So building gas-fired generating plants can both prevent the electricity supply crunch in 2015 and ensure that as more and more of our electricity comes from renewables we still have the flexibility to keep the lights on whenever we need them.

But we do also need to invest in more renewable gas production to make this strategy work. I was therefore delighted to hear on my visit to BioGenGreenfinch, arranged by the Midlands Co-op, that they are considering future sites producing gas to be fed directly into the gas grid as an alternative to electricity generation for the electricity grid.  ‘Green’ gas, as well as ‘green’ electricity will be vital for a sustainable future.

PS There’s now an article on this subject by me on Lib Dem Voice.

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